INVESTIGATIONS OF ENZYMATIC ALTERATIONS OF 2,4-DICHLOROPHENOL USING C-13-NUCLEAR MAGNETIC-RESONANCE IN COMBINATION WITH SITE-SPECIFIC C-13-LABELING - UNDERSTANDING THE ENVIRONMENTAL FATE OF THIS POLLUTANT

The biodegradation of C-13-labeled 2,4-dichlorophenol (DCP labeled at the C-2 and C-6 positions), in the presence and absence of natural org anic matter (NOM), by the white-rot fungus Phanerochaete chrysosporium , was examined using C-13-nuclear magnetic resonance (NMR). Using this method permitted the chemistry occurring at or near :the labeled site to be followed. The formation of alkyl ethers and alkene ethers was o bserved. No aromatic by-products were detected, indicating that aromat ic compounds are quickly degraded. Examining the reaction with time sh ows the exponential removal of 2,4-DCP and the consequential formation of labeled by-products, whose concentration reaches a maximum just be fore ail 2,4-DCP is consumed. After this, the by-products degrade expo nentially. The presence of NOM causes 2,4-DCP to be removed from the a queous phase more quickly than in its absence and also causes the by-p roducts to reach their maximum concentration much earlier. Degradation of the by-products occurs at a much greater rate in the presence of N OM. One hypothesis for this behavior is that the NOM interacts with 2, 4-DCP and its by-products, allowing them to be incorporated into the f ungal biomass. C-13-nuclear magnetic resonance spectra of the fungal b iomass after NaOH extraction show the presence of alkanes and a small amount of 2,4-DCP.